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    SubjectRe: [PATCH v2 09/18] ACPI / processor: Make it possible to get CPU hardware ID via GICC
    On Tue, Aug 19, 2014 at 09:37:34AM +0100, Hanjun Guo wrote:
    > On 2014-8-18 22:27, Catalin Marinas wrote:
    > > On Mon, Aug 04, 2014 at 04:28:16PM +0100, Hanjun Guo wrote:
    > >> diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c
    > >> index e32321c..4007313 100644
    > >> --- a/drivers/acpi/processor_core.c
    > >> +++ b/drivers/acpi/processor_core.c
    > >> @@ -64,6 +64,38 @@ static int map_lsapic_id(struct acpi_subtable_header *entry,
    > >> return 0;
    > >> }
    > >>
    > >> +/*
    > >> + * On ARM platform, MPIDR value is the hardware ID as apic ID
    > >> + * on Intel platforms
    > >> + */
    > >> +static int map_gicc_mpidr(struct acpi_subtable_header *entry,
    > >> + int device_declaration, u32 acpi_id, int *mpidr)
    > >> +{
    > >> + struct acpi_madt_generic_interrupt *gicc =
    > >> + container_of(entry, struct acpi_madt_generic_interrupt, header);
    > >> +
    > >> + if (!(gicc->flags & ACPI_MADT_ENABLED))
    > >> + return -ENODEV;
    > >> +
    > >> + /* In the GIC interrupt model, logical processors are
    > >> + * required to have a Processor Device object in the DSDT,
    > >> + * so we should check device_declaration here
    > >> + */
    > >> + if (device_declaration && (gicc->uid == acpi_id)) {
    > >> + /*
    > >> + * Only bits [0:7] Aff0, bits [8:15] Aff1, bits [16:23] Aff2
    > >> + * and bits [32:39] Aff3 are meaningful, so pack the Affx
    > >> + * fields into a single 32 bit identifier to accommodate the
    > >> + * acpi processor drivers.
    > >> + */
    > >> + *mpidr = ((gicc->arm_mpidr & 0xff00000000) >> 8)
    > >> + | gicc->arm_mpidr;
    > >
    > > You can use pack_mpidr_into_32_bits().
    >
    > processor_core.c will be used by x86 and ia64 too, it will cause
    > compile error on !ARM64 platforms.

    Oh. So we do we have an ARM-specific function in core ACPI code?

    --
    Catalin


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